Participants

• target population


  the group of individuals that a researcher is interested in studying
• sampling frames


  a group or population that is identified when it is unrealistic to study the whole target population
• random sampling


  a technique where participants are selected from the sampling frame and everyone has an equal chance of being selected eg. names pulled out of a hat, or a computer is used to randomly select participants
• strengths of random sampling

  -it is a fair method; the researcher cannot be accused of being biased in the way in which they selected the sample as everyone in the target population had an equal chance of being selected
• weaknesses of random sampling

  -you may end up with a biased sample; because the selection was due to chance there may be certain subgroups of the target population that are over or under represented in the sample
• opportunity sampling


  where participants are selected at the researchers convenience, without knowing any details about the sample in advance eg. people who are available at the time in their specific location
• strengths of opportunity sampling

  -easier for the researcher to administer in comparison to other sampling techniques, which may be more costly in time and resources
• weaknesses of opportunity sampling

  -may end up with a biased sample; because the selection was whoever was easier to access at the time and people tend to live with groups of people with similar attributes-may not be ethical; some students may feel obliged to take part in research projects for their university professors, therefore meaning they aren't giving valid consent.
• systematic sampling


  where every nth person on a list is selected by the researcher eg. every 5th person on a register
• strengths of systematic sampling

  -as long as the first participant is selected randomly, then the researcher cannot be accused of being biased in their selection of participants
• weaknesses of systematic sampling

  -as long as the first participant is selected randomly, then the researcher cannot be accused of being biased in their selection of participants
• stratified sampling


  where the target group is divided into subgroups eg. by sex and then participants are selected randomly from each subgroups
• strengths of stratified sampling

  -guarantee that all subgroups in the target population will be represented in the sample
• weaknesses of stratified sampling

  -it is more difficult for the researcher to administer in comparison to other sampling methods-participants randomly selected from each subgroup may not be representative of that subgroup
• quota sampling


  where the target population is divided into subgroups eg. by sex and the participants are chosen from each subgroups at the convenience of the researcher
• strengths of quota sampling

  -we can guarantee that all subgroups in the target population will be represented in the sample
• weaknesses of quota sampling

  -easier for the researcher to administer in comparison to other sampling techniques-participants opportunistically selected from each subgroup may not be representative of that subgroup
• self selected sampling


  where participants volunteer themselves for research eg. they come forward to the psychologist after seeing an advertisement
• strengths of self selected sampling

  -unlike other sampling techniques, we know everyone is interested in participating
• weaknesses of self selected sampling

  -people who volunteer may not be from appropriate subgroups within the target population-the researcher may not have sufficient participants who are willing to take part
• snowball sampling


  where participants are initially recruited by the psychologist and then those participants recruit further participants from people they know
• strengths of snowball sampling

  -helpful when trying to investigate a rare characteristic or behaviour
• weaknesses of snowball sampling

  -initial participants the researcher identifies may not know sufficient participants who share their rare characteristic-it can take more time to complete, as the researcher is having to wait and rely on their initial participants being able to contact other people who share their rare characteristic
• observational sampling techniques


  A sampling technique that is used to collect data about specific behaviours or events within specific time frames.
• event sampling


  Event sampling is where participants are observed by the psychologist, who records a specific behaviour (event) each time it occurs to create a total score.
• strengths of event sampling

  Event sampling is good because it records all the events during the observation, unlike some time sampling methods like time point sampling.

  Event sampling is more straightforward than time sampling for the researcher as they only need to identify a start and finish time, rather than recording each event in the correct interval.
• weaknesses of event sampling

  Event sampling is limited because it lumps all of the events together; it can’t tell us if a behaviour is more common at the start, middle or the end of the observation, which could be an important feature.

  Event sampling can also be overwhelming for researchers, as they are trying to record all events all the time.
• time sampling


  Where the psychologist observes and records behaviour (such as a score) at specific time intervals, e.g. every 15 minutes, and then creates an average score for each participant being observed.
• strengths of time sampling

  Time sampling is good because it can show us how a behaviour is spread out over an observation period, unlike event sampling which just records all instances of the behaviour together.

  Time sampling, especially time-point sampling, means that researchers do not get overwhelmed with data throughout the observation period, which can be an issue with event sampling.
• weaknesses of time sampling

  Time sampling is limited, because it may only record events or behaviours that occur at a specific point in time; if that behaviour isn’t occurring at the specific point in time that the researcher records the behaviour, then the behaviour goes unrecorded, unlike in event sampling.

  Time sampling can also be more complex to organise than event sampling. The researcher needs to keep track of the different time intervals when they are recording events, which can be quite confusing if they are observing multiple behaviours or participants.